Lithium (Li) ion battery packs, consisting of one or more Li ion cells, have found widespread adoption for various applications, including renewable energy systems and energy distribution systems. In particular, the high energy, high power density, and potential low cost of Li ion battery packs have made them particularly attractive in these applications. However, a major concern with Li ion battery packs is thermal management. That is, if the temperature of the battery pack is not maintained within a specific temperature range (e.g., −10° C. to 50° C.), the performance and lifetime of the Li ion cells therein can degrade significantly. Even worse, variations in temperature can cause different Li ion cells within a same battery pack or different battery packs in a same device to operate differently or unpredictably.